When recording an issue with HDMI it is very important that we know the following information:

Information required:

• The firmware version of the Mu-so mk2
• TV Make
• TV Model
• Any other devices connected to the TV (Makes & Models)
• Have they tried;
  • Check that the cable is up to spec: Is the HDMI cable HDMI v1.4 compliant? 
  • Check that the cable is properly seated. It is possible that if the cable is not properly inserted that the CEC switching will work but there is no audio. Remove and re-insert firmly.
  • Removing other devices connected and adding back in, one at a time 
  • Checking the HDMI cable is the correct version
  • Power cycling the TV whilst still connected
  • Is HDMI arc activated within the TV as standard or do they need to turn the feature on in the settings menu
  • Try switching the TV so it uses the external amplifier by navigating through the TV's menus to "audio output" and change "Internal speakers" to "External amplifier / ARC".
  • Changing the Auto Switching level in Naim APP -> Settings -> Input settings -> HDMI → HDMI Auto-Switching 
    • Does one work and not another?
• Any additional steps to produce the issue

THIS WILL GIVE US A SNAPSHOT OF THE CUSTOMERS SETUP ENVIRONMENT AND ISSUES